1. Field of Invention
The present invention relates to an image processing method and a module thereof, and more particularly to a method for processing a high dynamic range image (HDRI) and a module thereof.
2. Related Art
In current daily life, an image capturing device is widely used. The image capturing device captures an image with a light sensor and converts the image into digital signals, which are then stored. A variety of applications may be designed by means of the digital signals captured by the image capturing device in combination with a digital image processing technology.
The image capturing device is also applicable to a general pointing device, for example, an image mouse. The pointing device may emit a light ray to a surface, and the image capturing device captures a light ray reflected from the surface. After appropriate sampling, the pointing device may obtain images at multiple time points. A digital processor in the pointing device may compare images at adjacent time points, so as to determine a direction and distance of movement of the pointing device based on a brightness difference of pixels in the images.
However, when the image capturing device captures the light ray reflected from the surface, the reflected light ray may have unevenly distributed brightness because of the uneven brightness of the emitted light ray or a surface feature, so brightness of a large part of regions of the image may be too high, and the brightness of the other parts may be too low. The image with many pixels gathered at bright portions and dark portions is referred to as the HDRI. In the HDRI, the portions that are too bright and too dark lose original features of the image. In other words, when the image captured by the pointing device is the HDRI, a deviation occurs when the pointing device determines a direction and distance of movement because of a loss of details of the image.